A cellular wireless network may include a number of base stations that radiate to define wireless coverage areas, such as cells and cell sectors, in which user equipment devices (UEs) such as cell phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped communication devices, can operate. In turn, each base station may be coupled with network infrastructure that provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) and/or a packet-switched network such as the Internet for instance. With this arrangement, a UE within coverage of the network may engage in air interface communication with a base station and may thereby communicate via the base station with various remote network entities or with other UEs.
When a cellular wireless network serves UEs, the network may allocate various resources to facilitate communication to and from the UEs. In an example arrangement, for instance, the network may allocate “bearers” that define physical or logical communication channels extending between the UEs and a transport network. Each such bearer may be a “default bearer” or a “dedicated bearer” and may include a radio-bearer component that extends between a UE and a serving base station and an access-bearer component that extends between the serving base station and the transport network.
A dedicated bearer is a bearer on which the network is configured to give special treatment for communications. For instance, a dedicated bearer may provide a quality of service (QoS) having a “guaranteed bit rate” such that traffic delivered over the dedicated bearer may be delivered at the guaranteed bit rate or higher. A default bearer, on the other hand, is a bearer on which the network routes traffic with the best quality available at a given time (i.e., a “best effort” QoS). With a best effort service, a bit rate and/or delivery time of traffic delivered over the default bearer may vary based on a current traffic load of the network.
Further, both dedicated and default bearers may have a particular priority level based on a QoS class identifier (QCI) of each bearer, for instance. As such, in situations where the network is unable to accommodate delivery of traffic (e.g., due to a high volume of network traffic), the network may discard traffic on a lower priority bearer before discarding traffic on a higher priority bearer. Thus, in order to give special treatment to certain dedicated bearer traffic, some dedicated bearers may have a higher priority level than some default bearers.
In practice, the network may allocate a number of default and/or dedicated bearers for a UE to support various different types of communication services. By way of example, when the UE first enters into coverage of a base station, the UE may engage in a registration or “attachment” process that causes the network to allocate for the UE certain default bearers in accordance with the UE's service profile. For instance, if the UE's service profile indicates that the UE supports general packet-data communication (such as web browsing, file transfer, and the like), the network may allocate for the UE a default bearer for carrying such communications with a best-effort service level. Further, if the UE's service profile indicates that the UE supports voice over Internet Protocol (VoIP) communications or other such real-time packet-based communication service, the network may allocate for the UE a default bearer to support Session Initiation Protocol (SIP) signaling or the like to facilitate setup of such communications.
In turn, as a UE is being served by a base station, if the UE is going to engage in another type of communication service, the network may allocate for the UE still other bearers, such as a dedicated bearer. For instance, if the UE supports VoIP service and seeks to engage in a VoIP call, or a VoIP call server seeks to connect a call to the UE, the network may allocate for the UE a dedicated bearer having a guaranteed bit rate, and perhaps other high service level attributes, to carry the Val′ bearer traffic (e.g., packets representing voice), and the UE may then engage in the Val′ call via that bearer. Other examples are possible as well. Further, at the time of bearer establishment, the network may provide a traffic flow template (TFT) to a UE and its serving base station. Among other things, the TFT may indicate which traffic should be transmitted on the UE's dedicated bearer(s) and which traffic should be transmitted on the UE's default bearer(s).